1. Field of the Invention
The present invention relates to improvements in a loop-forming apparatus in a weaving machine for pile fabric, especially for weaving a web of surface fastener, and more particularly to such a loop-forming apparatus which is capable of arbitrarily defining the area of a loop-forming portion on a ground fabric woven continuously.
2. Description of the Prior Art
A known loop-forming apparatus in a weaving machine, for instance, as disclosed in Japanese Patent Laid-open Publication No. 57-14304, comprises a plurality of leno healds each including a pair of vertical guide wires having their central portions bent into an S shape and disposed on opposite side of a corresponding loop-forming bar or mandrel, and an inverted A-shaped half heald operatively interlocked with the guide wires and having at its bent portion an eyelet through which a loop-forming warp thread is threaded. The guide wires descend in alternate turns to lower the half heald to bring down the loop-forming warp thread alternately to one side and then to the other side of the loop-forming mandrels so as to pass the loop-forming warp thread over the mandrel, and thus forming a loop of the thread.
The known loop-forming apparatus has a drawback that it cannot cope with the trend of a high speed weaving machine, necessarily involves generation of unpleasant operation noise, and requires replacement of component parts having a relatively short period of use because the guide wires and halfheald operate with mutual physical contact. Another problem is that the conventional loop-forming apparatus requires a pair of guide wires and a half heald for a single loop-forming mandrel, which makes the apparatus complex with such an increased number of component parts as a whole.
The foregoing problems have been solved by a loop-forming apparatus disclosed, for example, in Japanese Patent Publication No. 1-39761 (U.S. Pat. No. 4,721,135). The disclosed loop-forming apparatus comprises a plurality of parallel spaced loop-forming mandrels each extending forwardly between and in parallel with respective adjacent pairs of ground warp threads beyond a cloth fell of a weaving machine, a leno deflector reciprocally movable in a transverse direction of the loop-forming mandrels for deflecting the course of loop-forming warp threads alternately to one side and then to the other side of the corresponding loop-forming mandrels, and a plurality of pairs of spaced gate hook bars each extending vertically at the opposite sides of the corresponding one of the loop-forming mandrels and vertically reciprocable to capture the laterally deflected loop-forming warp thread and then lower the same thread alternately at one side and then to the other side of the corresponding loop-forming mandrel to thereby form a loop of the thread. The thus arranged loop-forming apparatus is simple in construction having a reduced number of component parts, is capable of operating at a high speed by virtue of respective operative parts held out of mutual interference, and is free from any trouble caused by interference between adjacent loop-forming warp threads.
The loop-forming apparatus disclosed in the publications specified above and other conventional loop-forming apparatus incorporated in the weaving machines for weaving a web of surface fastener are so constructed as to form a plurality of rows of loops continuously as the weaving of a ground fabric progresses. They have neither an intention of alternately forming a loop-forming surface and a loop-free surface, nor the idea of restricting a loop-forming surface within a given area.
The surface fasteners are used in various ways. In one mode of application, they are used on a fastening portion or area of a binding or fastening strip in which instance the binding strip as a whole may be composed of a surface fastener tape having male or female interlocking elements, and a piece of surface fastener tape having female or male interlocking elements is attached to one end portion of the back surface of the binding strip. In the binding strip, however, these interlocking elements which are located on a portion other than the fastening portion are left unused and hence can be dispensed with. Accordingly, if the interlocking elements could be formed only on the necessary portion of a binding strip at the time of weaving of the binding strip, a considerably improvement in the productivity should be provided with the resultant reduction of cost. In recent years, the surface fasteners have found their application for an attachment device for curtains. In this case, it would be particularly advantageous if a first surface having male or female interlocking elements and a second surface free from interlocking elements could be formed at a given interval while restricting the respective areas of the first and second surfaces.
The above-described conventional weaving machines, however, cannot produce loop-forming surfaces and loop-free surfaces arranged alternately. If an attempt to form the loop-forming surfaces and loop-free surfaces alternately were made on a weaving machine equipped with the leno-heald type loop-forming apparatus, it would require a large-sized chain and cam mechanism which will enlarge the overall size of the apparatus, and also need the use of an expensive weaving machine such as a jacquard machine or a dobby machine.